*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #f5f5f5;
  --surface: #ffffff;
  --surface-2: #f0f0f0;
  --border: #d1d5db;
  --text: #1f2937;
  --text-muted: #6b7280;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --accent-soft: #eff6ff;
  --danger: #dc2626;
  --danger-soft: #fef2f2;
  --success: #16a34a;
  --success-soft: #f0fdf4;
  --warning: #d97706;
  --warning-soft: #fffbeb;
  --radius: 8px;
  --radius-sm: 4px;
  --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
  --font-mono: 'Cascadia Code', 'Fira Code', 'Consolas', 'Monaco', monospace;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

[data-theme="dark"] {
  --bg: #0f172a;
  --surface: #1e293b;
  --surface-2: #334155;
  --border: #334155;
  --text: #f1f5f9;
  --text-muted: #94a3b8;
  --accent: #3b82f6;
  --accent-hover: #60a5fa;
  --accent-soft: #1e3a5f;
  --danger: #f87171;
  --danger-soft: #3b1212;
  --success: #4ade80;
  --success-soft: #0f2d1a;
  --warning: #fbbf24;
  --warning-soft: #2d1f07;
  --shadow: 0 1px 3px rgba(0,0,0,0.4);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.3);
}

html { font-size: 15px; }

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background 0.2s, color 0.2s;
}

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hover); }

button {
  font-family: var(--font-sans);
  cursor: pointer;
  border: none;
  outline: none;
  transition: background 0.15s, color 0.15s, opacity 0.15s;
}

button:disabled { opacity: 0.45; cursor: not-allowed; }

code, pre {
  font-family: var(--font-mono);
  font-size: 0.875rem;
}

.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
}